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Publication numberUS4851912 A
Publication typeGrant
Application numberUS 07/221,005
Publication dateJul 25, 1989
Filing dateJul 18, 1988
Priority dateMar 6, 1986
Fee statusPaid
Publication number07221005, 221005, US 4851912 A, US 4851912A, US-A-4851912, US4851912 A, US4851912A
InventorsRichard A. Jackson, Kevin D. Windrem
Original AssigneeThe Grass Valley Group, Inc.
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Apparatus for combining video signals
US 4851912 A
Abstract
A first shaped video signal V1 K1 and a second shaped video signal V2 V2, are combined so as to generate a third shaped video signal V3 ' given by
V3 '=V1 K1 [1-K2 (1-P12)]+V2 K2 
(1-K1 P12)
where P12 is a priority signal. A key signal K3 given by
K3 =1-(1-K1)(1-K2)
is also generated. An output processor receives the shaped video signal V3 ', the key signal K3 and a matte signal M3. In a first mode of operation, the output video signal V3 " of the output processor is given by
V3 "=V3 +M3 (1-K3)
and the key signal K3 ' that is generated by the output processor has a constant value, and in a second mode of operation of the output processor the output video signal is given by
V3 "=V3 '/K3 
and the key signal K3 ' is directly proportional to K3.
Images(4)
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Claims(11)
We claim:
1. Apparatus for combining a first shaped video signal V1 K1 and a second shaped video signal V2 K2 in accordance with a priority signal P12, comprising:
means for generating from said first and second shaped video signals and said priority signal a third shaped video signal V3 ' given by
V3 '=V1 K1 (1-K2 (1-P12))+V2 K2 (1-K1 P12)
where V1 is a first unshaped video signal, V2 is a second unshaped video signal, K1 is a first key signal associated with the first unshaped video signal and K2 is a second key signal associated with the second unshaped video signal; and
means for generating from the first and second key signals a third key signal K3 given by
K3 =1-(1-K1)(1-K2).
2. Apparatus according to claim 1, further comprising an output processor for receiving the third shaped video signal V3 ' and the third key signal K3, said output processor being operative in a first mode to generate an output signal V3 " given by
V3 "=V3 '+A
where A is a function of the third key signal and is independent of V3 ', and a key signal K3 ' having a constant value.
3. Apparatus according to claim 2, wherein the output processor is operative in a second mode to provide the output signal V3 " as a function that is directly proportional to the ratio of V3 '/K3, and the key signal K3 ' as a function that is directly proportional to the third key signal K3.
4. Apparatus according to claim 2, wherein the output processor has an input terminal for receiving a matte signal M3 and is operative in the first mode to generate the output video signal V3 " where
A=M3 (1-K3).
5. A processing circuit for receiving a shaped video signal V3 ' and an associated key signal K3 and providing output signals in response thereto, said processing circuit having at least a first mode of operation and comprising means operative in the first mode of the processing circuit to generate from the shaped video signal and the associated key signal an output video signal V3 " as one of the output signals given by
V3 "=V3 '+A
where A is a function of the associated key signal and is independent of V3 ', and an output key signal as another of the output signals having a constant value.
6. A processing circuit according to claim 5, having a second mode of operation, and wherein the operative means in the second mode generates the output video signal V3 " according to
V3 "=CV3 '/K3 
where C is a constant, and the output key signal having a value that is directly proportional to the associated key signal K3.
7. A processing circuit according to claim 5, further comprising an input terminal for receiving a matte signal M3 such that in the first mode the operative means generates the output video signal V3 " where
A=M3 (1-K3).
8. A combiner system for combining more than two shaped video signals with respective associated key signals and a plurality of priority signals comprising:
a plurality of combiner cells, each combiner cell having as inputs two of said shaped video signals and their respective associated key signals together with one of the priority signals and having as outputs an output shaped video signal and an associated output key signal, the combiner cells being connected in cascade such that the output shaped video signal and the associated output key signal form one of the shaped video signals and its respective associated key signal input to the succeeding combiner cell; and
a plurality of output processors, one for each of the combiner cells, having as inputs the output shaped video signal and its associated output key signal from the respective combiner cells and having as outputs an unshaped video signal and an associated key signal output.
9. A combiner system as recited in claim 8 further comrising means for applying the outputs from the last combiner cell in the cascade to the inputs of the first combiner cell in the cascade in lieu of one of the shaped video signals and associated key signal to establish a closed ring.
10. A combiner system for combining more than two shaped video signals with respective associated key signals and a plurality of priority signals comprising:
a plurality of combiner cells, each combiner cell having as inputs two of said shaped video signals and their respective associated key signals together with one of the priority signals and having as outputs an output shaped video signal and an associated output key signal, the combiner cells being connected in cascade such that the output shaped video signal and the associated output key signal form one of the shaped video signals and its respective associated key signal input to the succeeding combiner cell; and
an output processor having as inputs the output shaped video signal and its associated output key signal from a predetermined one of the combiner cells and having as outputs an unshaped video signal and an associated key signal output.
11. A combiner system as recited in claim 10 further comprising means for applying the outputs from the last combiner cell in the cascade to the inputs of the first combiner cell in the cascade in lieu of one of the shaped video signals and its associated key signal to establish a closed ring.
Description

This is a continuation of application Ser. No. 836,945, filed Mar. 6, 1986, and now abandoned.

This invention relates to apparatus for combining video signals.

BACKGROUND OF THE INVENTION

In a video mixer, two video signals V1 and V2 (FIG. 1) are multiplied by a key signal K1 (having a range of values from 0 to 1) and its complement (1-K1) respectively, and the two signals V1 K1 and V2 (1-K1) are additively combined in a summer to produce a composite output signal Vq having the form V1 K1 +V2 (1-K1). When the key signal K1 is zero, the input signal V1 makes no contribution to the signal Vq, regardless of the value of V1. Similarly, if K1 is one, the signal V2 makes no contribution to the signal Vq. The proportion of the signal Vq that is contributed by V1 determines the opacity with which the scene represented by the signal V1 is perceived in the composite picture. If K1 is one, i.e., V1 represents 100% of the signal Vq, then the V1 scene (the scene represented by the signal V1) completely obscures the V2 scene, regardless of the value of V2. As K1 decreases, the extent to which the V2 scene is obscured in the composite picture is reduced until, when K1 reaches zero, the V2 scene is opaque and completely obscures the V1 scene. Thus, the coefficients K1 and (1-K1) determine the relative opacity of the two component scenes: if the coefficient K1 is greater than (1-K1), then the V1 scene at least partially obscures the V2 scene and appears, to a viewer of the composite scene, to be in front of the V2 scene.

The multiplication of the signals V1 and V2 by the key signal K1 and its complement (1-K1) is shown in FIG. 1, in which it is assumed that all signals have five discrete values in the range from zero to unity and have sharp transitions between levels. It will, of course, be appreciated that FIG. 1 is in fact very much simplified, and that in the case of analog signals the range of possible values is continuous, and that transitions for either analog or digital signals would have a finite slew rate.

A video signal V1 ' is said to be a "shaped" video signal when it is the multiplication product of an unshaped video signal V1 and an associated key signal K1. In general, there is no necessary relationship between the video signal and its associated key signal. A production switcher normally receives unshaped video signals and their associated key signals and provides a full screen video signal at its output. No key output is produced.

Shaping has two aspects, namely spatial or X-Y shaping (only the X-dimension is shown in FIG. 1), which determines the area of the composite picture to which the component signal makes a contribution (when K1 =0, the signal V1 makes no contribution to the signal Vq), and opacity or Z shaping, which determines, for K1 greater than zero, the magnitude of the contribution that is made by the component signal to the composite signal Vq. The shaping of the component signals is discussed in terms of "coverage" in Porter, T. and Duff, T., "Compositing Digital Images", Computer Graphics, Vol. 18, No. 3 (1984), pages 253 to 259.

The foregoing discussion of the manner of production of the signal Vq is based on the assumption that the signal V2 is a full field signal, i.e. that the key signal K2 associated with the video signal V2 is one for all locations. In the general case, K2 is not one for all locations and

Vq =V1 K1 +V2 K2 (1-K1)

It will be seen from this more general expression that the video signal Vq, being the weighted sum of two shaped video signals V1 K1 and V2 K2, is itself a shaped video signal. For the sake of consistency in notation, the shaped signal that has previously been designated Vq will hereafter be designated Vq ', and Vq will hereafter be used to designate the corresponding unshaped signal.

The key signal Kq that relates Vq ' to Vq is given by

Kq =1-(1-K1)(1-K2)

If, for every location, either K1 or K2 is one, then Kq =1 for all locations. In particular, if either V1 or V2 is a full field signal, the signal Vq ' is a full field signal. If, on the other hand, Vq ' is not a full field signal it might be desired to form a composite scene from the scenes represented by the signal Vq ' and, e.g., a background scene represented by a signal Vr having an associated key signal Kr. In such a case, the signal (1-Kq) would be used to process the signal Vr in a production switcher, and an output signal Vs '=Vq '+Vr Kr (1-Kq) would be produced. Generally, Vr would be a full field signal and so Kr =1 and Vs '=Vq '+Vr (1-Kq).

Recalling that Vq '=V1 K1 +V2 K2 (1-K1), if K1 =1, then Vq '=V1, i.e. the signal V2 makes no contribution to the signal Vq ', regardless of the value of K2. Therefore, combining of the video signals V1 and V2 is under the primary control of the key signal K1. Similarly, if the signal Vq ' were equal to V1 K1 (1-K2)+V2 K2, the combining would be under the primary control of the signal K2, and if K2 =1, then Vq '=V2 and V1 makes no contribution regardless of the value of K1. The two different situations are equivalent respectively to the V1 scene and the V2 scene being in the foreground of the composite scene. However, the conventional mixer does not allow the operator to control on a dynamic basis whether the mixing operation is under the primary control of the signal K1 or of the signal K2.

SUMMARY OF THE INVENTION

In a preferred embodiment of the invention, first and second shaped video signals V1 ' and V2 ' are combined in accordance with associated first and second key signals K1 and K2 and a priority signal P12, by generating a third shaped video signal V3 ' which is given by

V3 '=V1 '[1-K2 (1-P12)]+V2 '(1-K1 P12)

and a third key signal K3 which is given by

K3 =1-(1-K1)(1-K2).

The value of the priority signal P12 determines the relative weighting given to the key signals K1 and K2 in forming the third video signal V3 ', and this in turn determines whether the scenes represented by the component signals V1 and V2 are perceived in the composite picture as representing foreground objects or background objects. The priority signal P12 may be varied over several frames of the video signals, so that the background objects appear to pass through the foreground objects and become foreground objects themselves. In a split-screen effect, by having a change in the value of the priority signal P12 occur at the split, objects that appear to be in the foreground on one side of the composite image can be made to appear in the background on the other side of the composite image, and vice-versa.

It will be appreciated that in the context of the present invention, references to component video signals are intended to relate to signals that represent different scenes, and that references to a composite video signal are intended to relate to a signal that represents a scene formed by combining two or more scenes, as represented by respective component video signals.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which:

FIG. 1 shows waveforms to illustrate combining of video signals,

FIG. 2 is a block diagram of a combiner cell for combining first and second component video signals,

FIG. 3 is a block diagram of a combiner system comprising several combiner cells connected in a cascade arrangement, and

FIG. 4 is a block diagram of an output processor for a combiner cell.

DETAILED DESCRIPTION

The combiner cell shown in FIG. 2 comprises multipliers 4, 6, 8, 10 and 12, complement circuits 14, 16, 18, 20, 22 and 24, and a summer 26. The illustrated combiner cell operates in the digital domain with parallel data, and therefore all the signal lines that are illustrated would in fact be multiple conductor lines. Additional circuitry would be required to assure proper timing relationships among the various signals, but such matters are well within the skill of the art and therefore are not shown and will not be further described.

The input signals of the combiner cell comprise two shaped video signals V1 ' and V2 ', associated key signals K1 and K2, and a priority signal P12. The levels of the key signals K1 and K2 and the level of the priority signal P12 are normalized to have maximum and minimum values that can be represented numerically as 1 and 0. Also, the video signals V1 ' and V2 ' gave the same maximum and minimum values. Additional multipliers 2 and 3 are provided upstream of the combiner for generating the shaped video signals V1 ' and V2 ' from unshaped video signals V1 and V2 and the associated key signals K1 and K2. The combiner cell provides a shaped output video signal V3 ' and an output key signal K3. It can readily be seen that the output video signal is given by the equation

V3 '=V1 '[1-K2 (1-P12)]+V2 '(1-K1 P12)

and that the output key signal is given by

K3 =1-(1-K1)(1-K2).

The value of P12 determines the weighting factors that are applied to the two video signals V1 ' and V2 '. If P12 is equal to zero, this implies that the V2 scene is in the foreground of the composite scene and that the V1 scene is in the background, and vice versa if P12 is equal to one.

For P12 =0, then

V3 '=V1 '(1-K2)+V2 '

The value of K2 defines areas in which the V2 scene contributes to the composite scene. If K2 =1, the contribution of V1 to the composite scene is zero and therefore the V2 scene completely obscures the V1 scene. If K2 =0, V2 '=0 and therefore there is no contribution from V2 and V1 is allowed to pass to V3 ' unaltered.

For P12 =1, then

V3 '=V2 '(1-K1)+V1 '

The value of K1 defines areas in which the V1 scene contributes to the composite scene. If K1 =1, the contribution of V2 to the composite scene is zero and therefore the V1 scene completely obscures the V2 scene. If K1 =0, there is no contribution from V1 and V2 is allowed to pass to V3 ' unaltered.

For P12 =0.5, then

V3 '=V1 '(1-K2 /2)+V2 '(1-K1 /2)

Where K2 =0, V1 ' is passed unaltered; where K1 =0, V2 ' is passed unaltered; and where K2 >0 and K1 >0, the relative opacities of the V1 and V2 scenes are determined by the ratio of K1 and K2.

As P12 increases from zero the relative depths of the V1 and V2 pixels in the composite image change, from the V2 pixel appearing in front of the V1 pixel, through the two pixels appearing to be at the same depth (at P12 =0.5), to the V1 pixel appearing in front of the V2 pixel. It will therefore be seen that the priority signal P12 makes it possible to determine which of the component scenes will appear as the foreground scene in the composite picture. By changing the value of P12, the composite picture can be changed so that a component scene is the foreground scene at one time and is the background scene at another time.

Several combiner cells 30, 40 . . . 90 of the kind shown in FIG. 2 may be connected in cascade, as shown in FIG. 3, to form a combiner system. Output processors 32, 42 . . . 92 are associated with the combiner cells respectively, for a reason which will be explained below. The output signals from the output processors are connected to a production switcher.

Conventional production switchers are designed to receive unshaped video signals and their associated key signals, and multiply the video signals by their key signals to produce shaped video signals that are combined with other shaped video signals, e.g., a signal generated by a digital video effects unit, to produce a final program video signal representing the desired composite picture. The output video signals provided by the combiner cells are already shaped by their respective key signals. If the signal V3 ', for example, is applied to a conventional production switcher it will be shaped a second time, and the result will be a black halo in the scene represented by the signal V3 ' for values of K3 greater than zero and less than unity. The output processors are interposed between the combiner cells and the production switcher in order to generate unshaped video signals from the shaped video signals generated by the combiner cells.

FIG. 4 shows the output processor associated with the combiner cell 30. The other output processors are identical. As shown in FIG. 4, the output processor 32 receives the shaped video signal V3 ' and the key signal K3 from the associated combiner cell 30, and also receives a video matte signal M3. The signal M3 represents a background for the V3 scene. The background may be, for example, a plain, solid color. The output processor comprises a summer 102, a multiplier 104, a divider 106 (implemented as a reciprocal look-up table 108 and a multiplier 110) and a complement circuit 112. In addition, the processor comprises a switch 114 for selecting one of two operating modes for the processor. The processor provides a composite output video signal V3 " and a composite output key signal K3 ', which are applied as input signals to the production switcher.

In the first mode of operation of the processor (background on), the signal V3 " is given by

V3 "=V3 '+A

where A=M3 (1-K3) so that

V3 "=V3 '+M3 (1-K3).

Thus, for any pixel for which K3 is zero, V3 '=0 and V3 "=M3. If K3 is not zero, indicating that V3 ' is non-zero, the relative contribution of V3 ' to V3 " depends on the value of K3, and it can be seen that for K3 =1, M3 is not permitted to make a contribution and V3 "=V3 '. The output key signal to inhibit the production switcher from attempting to add another background.

In the second mode of operation (background off), the output key signal K3 ' is equal to K3, and the production switcher will then add background to pixels for which K3 ' is not 1.0 in proportion to the value of (1-K3). The production switcher will multiply V3 " by K3 '. Since K3 ' is equal to K3, it is desired for the reason indicated above that V3 " not be equal to V3 '. Therefore, in the second mode the output signal V3 ' from the summer 102 is divided by the key signal K3, so that

V3 "=V3 '/K3.

Therefore, the signal V3 " is equal to V3 (which does not actually exist), and the switcher may multiply the signal V3 " by K3 ' (which is equal to K3) and produce the desired signal V3 ' at the switcher output. For pixels at which K3 is close to zero, V3 " is indeterminate, but this is not important to the final program video signal because these pixels make no contributiion to that signal.

It will be appreciated that the invention is not restricted to the particular apparatus that has been described and illustrated, and that variations may be made therein without departing from the scope of the invention as defined in the appended claims, and equivalents thereof. For example, instead of using interdependent processing circuits for generating, from K1, K2 and P12, the multiplication factors for the video signals V1 and V2, these multiplication factors may be generated independently, as mix constants that are separately applied to the multipliers of a signal mixer that is of otherwise conventional form. It is not necessary that each combiner cell of the system shown in FIG. 3 should have its own output processor, since if the output is always to be taken from the same combiner cell, it is necessary only that an output processor be associated with the combiner cell. In a preferred implementation of the invention, the key and video output signals of the last combiner cell in the cascade are connected as inputs to the first combiner cell, so as to establish a closed ring. This provides additional flexibility, in that the ring can be logically broken at any point, allowing additional priority combinations. For example, in the arrangement shown in FIG. 3 the signal V4 ' can only be combined with the composite signal V1 '/V2 ', and the component signal V9 ' can only be combined with the composite signal V1 '/ . . . /V8 '. The scene represented by the signal V9 ' cannot be made to appear behind the V1 scene but in front of the V4 scene. However, if the switches 94 are operated so that the output signals V9 ' and K9 are applied to the combiner cell 30 in lieu of the input signals V2 ' and K2, and P12 and P34 are set to unity, the desired composite signal would be provided at the output of the output processor 42 (V5 ", K5 '). The key signal K8 must be forced to zero inside the combiner cell 90.

It will also be appreciated that although the preferred embodiment of the invention, described above with reference to the drawings, is implemented using parallel digital data, it could also be implemented using serial digital data or analog data.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3673324 *Dec 22, 1970Jun 27, 1972Nippon Electric CoVideo mixing/special effects amplifiers
US4028727 *May 7, 1976Jun 7, 1977Central Dynamics Ltd.Mix/effects switch arrangement and mix/effects switching system
US4420770 *Apr 5, 1982Dec 13, 1983Thomson-Csf Broadcast, Inc.Video background generation system
Non-Patent Citations
Reference
1 *Compositing Digital Images (Porter/Duff) 1984.
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4947254 *Apr 27, 1989Aug 7, 1990The Grass Valley Group, Inc.Layered mix effects switcher architecture
US5146333 *Oct 6, 1989Sep 8, 1992The Grass Valley Group, Inc.Self keyer with pre-emphasized fill video
US5153711 *Sep 16, 1991Oct 6, 1992The Grass Valley Group, Inc.Recursive video hue rotations to obtain a rainbow-like decaying after-image
US5166797 *Dec 26, 1990Nov 24, 1992The Grass Valley Group, Inc.Video switcher with preview system
US5227863 *Aug 7, 1990Jul 13, 1993Intelligent Resources Integrated Systems, Inc.Programmable digital video processing system
US5231499 *Feb 11, 1991Jul 27, 1993Ampex Systems CorporationKeyed, true-transparency image information combine
US5280337 *Oct 13, 1992Jan 18, 1994The Grass Valley Group, Inc.Depth-based video combining
US5327177 *May 26, 1992Jul 5, 1994The Grass Valley Group, Inc.Method of and apparatus for processing a shaped video signal to add a simulated shadow
US5353068 *Aug 17, 1993Oct 4, 1994Sony CorporationVideo signal combining apparatus and method
US5408272 *Dec 13, 1993Apr 18, 1995The Grass Valley Group, Inc.Method of producing a composited video image based on depth
US5416529 *Jan 14, 1994May 16, 1995ImmixMethod and system for digital video processing with combined downstream keyer and fade to black mixer
US5428401 *May 8, 1992Jun 27, 1995Quantel LimitedImprovements in or relating to video image keying systems and methods
US5657095 *Mar 19, 1996Aug 12, 1997Pioneer Electronic CorporationSystem for Combining image signals
US5668639 *Mar 21, 1995Sep 16, 1997Comunicacion IntegralMethod for video editing
US5689310 *Oct 23, 1995Nov 18, 1997Sony CorporationFor processing a digital picture
US5825433 *Dec 7, 1995Oct 20, 1998Matsushita Electric Industrial Co., Ltd.Video mixing apparatus
US5877818 *Mar 26, 1997Mar 2, 1999Sony CorporationSpecial effect picture device
US6310658 *Aug 27, 1998Oct 30, 2001Samsung Electronics Co., Ltd.Video signal mixing apparatus and method thereof
US6931511Dec 31, 2001Aug 16, 2005Apple Computer, Inc.Parallel vector table look-up with replicated index element vector
US7034849 *Dec 31, 2001Apr 25, 2006Apple Computer, Inc.Method and apparatus for image blending
US7055018Dec 31, 2001May 30, 2006Apple Computer, Inc.Apparatus for parallel vector table look-up
US7230633 *Jan 11, 2006Jun 12, 2007Apple Inc.Method and apparatus for image blending
US7467287Dec 31, 2001Dec 16, 2008Apple Inc.Method and apparatus for vector table look-up
US7548248Jun 7, 2007Jun 16, 2009Apple Inc.Method and apparatus for image blending
US7681013Dec 31, 2001Mar 16, 2010Apple Inc.Method for variable length decoding using multiple configurable look-up tables
DE4230008A1 *Sep 8, 1992Mar 18, 1993Grass Valley GroupRekursive video-farbtondrehungen zum erhalt eines regenbogenartigen abklingenden nachbildes
DE4311479A1 *Apr 7, 1993Oct 14, 1993Grass Valley GroupVorrichtung und Verfahren für Autoübersetzungsrekursiveffekte
DE4315523C2 *May 10, 1993Feb 1, 2001Grass Valley GroupChroma-Keyer mit sekundärem Farbtonwähler
DE4444304A1 *Dec 13, 1994Jun 14, 1995Grass Valley GroupVerfahren zum Erzeugen eines zusammengesetzten Videobildes
Classifications
U.S. Classification348/585, 348/E05.056, 348/588, 348/586
International ClassificationH04N5/265
Cooperative ClassificationH04N5/265
European ClassificationH04N5/265
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